TWIN PEAKS Tap Tremolo (Y.A.H.T: Yet Another Harmonic Tremolo)

[drolo]

See, that is precisely why I gave up the Zener idea and decided on voltage regulators. Read a scary thread about zeners where someone (R.G.?) warned that mere mortals would have a hard time figuring out how to calculate the resistance to make them function properly ;-)

I have no clue how to calculate the impedance of the circuit. Would it help to have the current consumption? Would that be as easy as measuring the voltage across R16 and calculate I = V/R ? Also I noticed that as the optos light up, especially when they are set to work in phase, the voltage sags a bit. Could that complicate things? I guess I would need to measure the voltage across R16 when the Leds are lit on maximum.

[Valoosj]

For current consumption you can just stick your DMM in series between your power source and your pedal. Then you can use the calculation of my previous post. The maximum resistance for the series resistor however, is one I'm very unsure about. If it's too high, the Zener will eat a lot of current and get hot. And there was my question about what happens if your input voltage goes below 9.1V.

As for the voltage sag, I assume that if the series resistor is within the proper range, it won't be a big issue. But yes, I think someone like R.G. would be very helpful to ensure we're on the right path here.

[drolo]

For current consumption you can just stick your DMM in series between your power source and your pedal.

I forgot to mention why I would need to calculate the current instead of measuring it, the Amperemeter on my DMM for some reason is shot ...

[drolo]

Ok, I measured the current going to the 2 op amps U3. It draws 15ma when both optos are fully lit. at least in my setup, current draw may vary depending on what optos are used and how they are biased. BTW I experimented with different op amps and found the 5532 to work better than the 1458 and 4558 and tl072 I had around. They had the widest swing, exactly 5V.

[Valoosj]

My 5532 did not work at all for some reason.

[drolo]

My 5532 did not work at all for some reason.

weird ... I tried 2 different ones and both worked fine
next best, 1458 and 4558
TL072 was not so good

[Valoosj]

When using the following schematic ...


First I would need to find out the equivalent load resistance of the circuit.
I am feeding it with a onespot which puts out 9.4V.

My DMM says I am using about 20mA. It goes up to 60mA if I set the brightness of the rate LED very high.

Because R = V/I = 9.4V / 20mA = 470 Ohms.

To calculate the series resistance, I need to know which input voltages I would allow. Let's say 9-10V.

My zener is 500mW.

500mW/9.1V =  54.9mA and so,

R1_min = (10V-9.1V)/( 20mA + 54.9mA) = 12 Ohms.

For real zeners a more practical rule of thumb is to ensure the zener current doesn't drop below about 1/10th it's maximum current.  

In this case the minimum zener current would be 5.5mA and

R1_practical_minimum = (10V-9.1V)/( 20mA + 5.5mA) = 35 Ohms

Rs_max = 9.1V/55mA = 165 Ohms


I get the feeling I am missing something here. Any insights from the smarter minds? Please?

[drolo]

Slight schematic update:



Added a different voltage regulator for the LED driver section.
When I drew the schematics, I had not realized 7808's did not exist, and even if they did, there would not be enough headroom for the regulator to operate with a 9V supply.

Using a 7806 and juicing the voltage up with a LED gives enough headroom for the 5532 not to clip the PWM signal.

Also increased C5 in the highpass and reduced R18 for a less harsh treble. Sounds rounder now :-)

[Koopa]

This is easily THE BEST tremolo pedal I've heard! Creative work!

I've been wondering if this has gone commercial already or is this stuff free to be used if I build my own copy of this design? I'm new to this site and this DIY-pedal stuff also. But tremolo pedal is something I've wanted to do for a while and then I found this! Amazing..

Is it ok if I (try to) build my own COPY of this? If yes..in that case I would have a couple of questions about this circuit.

1) In some schematic resistor R27 3M5 was missing. I assume that this last posted schematic is the updated one?
2) Will it work if I go with the last schematic you've posted? There was some discussion about the regulators and I am kind of confused right now how to make it. You said you didn't use them at all? So what would be the right way to do the connections?
3) I guess this is kind of a dumb question but I'm new to this stuff so nothing is obvious for me yet You didn't draw the bypass switch here at all. I guess that it is so obvious to everybody how to do it (except for me) that you didn't even draw it here? Just regular bypass option before 'IN', is that correct?
4) You said that there was some humming and then you used protected cable somewhere to get rid of that sound. Which part exactly you protected with grounded wire?
5) Ground of Input and Output cables to the same potential of battery minus? Or do you just connect the grounds from input and output and leave the battery minus independent and separate?
6) About components: Do I have to worry about the sensitivity of the components (Max voltages, etc..)? That XTAL component..what is it? I found 4 LEDS from the circuit. 1.8 V all of them? Is the indicator which tells if the tremolo is on/off separate from these schematics? I guess it goes to the bypass circuit.
7) According to those six questions, should I even try?


Thanks in advance!

[drolo]

>  I've been wondering if this has gone commercial already or is this stuff free to be used if I build my own copy of this design? I'm new to this site and this DIY-pedal stuff also. >  But tremolo pedal is something I've wanted to do for a while and then I found this! Amazing..

>  Is it ok if I (try to) build my own COPY of this? If yes..in that case I would have a couple of questions about this circuit.

You are free to use it for non-commercial purposes.

> 1) In some schematic resistor R27 3M5 was missing. I assume that this last posted schematic is the updated one?

Not sure where you saw that resistor, but indeed the schematic posted last is the most recent one.

> 2) Will it work if I go with the last schematic you've posted? There was some discussion about the regulators and I am kind of confused right now how to make it. You said you didn't use them at all? So what would be the right way to do the connections?

The method iin the last schematic works very well.

> 3) I guess this is kind of a dumb question but I'm new to this stuff so nothing is obvious for me yet You didn't draw the bypass switch here at all. I guess that it is so obvious to everybody how to do it (except for me) that you didn't even draw it here? Just regular bypass option before 'IN', is that correct?

That's correct. If you are new to this I invite you to have a look at the beginners corner for a good start. lots of good info on the basics:

http://diystompboxes.com/wiki/index.php?title=Main_Page

http://www.diystompboxes.com/smfforum/index.php?board=10.0

> 4) You said that there was some humming and then you used protected cable somewhere to get rid of that sound. Which part exactly you protected with grounded wire?

Actually I have been building these without shielded wire and have no issues. I got this noise while testing a board outside a box with long flying leeds.

> 5) Ground of Input and Output cables to the same potential of battery minus? Or do you just connect the grounds from input and output and leave the battery minus independent and separate?

What you really need to do is keep the grounds from the audio circuit and those from the microprocessor and the led drivers separate. Only joining at one ccommon ground, at the power supply for example.

> 6) About components: Do I have to worry about the sensitivity of the components (Max voltages, etc..)? That XTAL component..what is it? I found 4 LEDS from the circuit. 1.8 V all of them? Is the indicator which tells if the tremolo is on/off separate from these schematics? I guess it goes to the bypass circuit.

Since it is to be operated at 9V I would use components that are rated at 15V at least.
Xtal stands for Crystal, in this case a 20MHz one (forgot to specify) It's a reference clock for the microprocessor.
D3 and D4 are the LEDs contained in the vactrols. The other ones can be whatever you like. Perhaps use a superbright for D2 to have less current spikes and less danger of ticking.
The bypass indicator is indeed not shown in the schematic, same with the bypass.

> 7) According to those six questions, should I even try?

Worst thing that can happen is that it does not work  ;-)
Perhaps if you are uncertain, try to start with something a bit easier, like a booster or an overdrive, at least to get used to the basics.

Good luck and fun in your endeavors :-)

[Koopa]

Thank you for your quick response!

Those really answered all my questions..Perhaps I'll start with a Keeley compressor first And definitely will look for those links you posted.

You should really commercialize this! MadProfessor? Boss?

And yes, no intentions to sell your design anywhere  
Let's keep this hipster before it goes down the mainstream.

[Neur0]

Hello,

Digging up an "old" but great thread.
I had the Tremulus Lune on my list for building and it would be by far the most ambitious build  to date for me. That is until I came across this little gem
David, on your website you show a gut shot with a double sided PCB which was discussed earlier. Are they available for purchase from you or anyone else?
It would take me quite some time to design one myself with DipTrace, not to mention far worse than what you probaly have

Kind regards,
Remy van Noorden

[drolo]

Hello,

Digging up an "old" but great thread.
I had the Tremulus Lune on my list for building and it would be by far the most ambitious build  to date for me. That is until I came across this little gem
David, on your website you show a gut shot with a double sided PCB which was discussed earlier. Are they available for purchase from you or anyone else?
It would take me quite some time to design one myself with DipTrace, not to mention far worse than what you probaly have

Kind regards,
Remy van Noorden

Yes I have some PCB's available. I have sent you a PM

[Neur0]

All done and sorted.

Thank you very much, David 

[MAndrews]

Hi David. Been watching the demo of your tremolo and it sound wonderful - gave me goosebumps! I know it is a long time since anyone posted in this thread but I wondered if you still had any PCBs.

Thanks.

Mark.

[soderstrom]

Hi David. Been watching the demo of your tremolo and it sound wonderful - gave me goosebumps! I know it is a long time since anyone posted in this thread but I wondered if you still had any PCBs.

Thanks.

Mark.

Hi David, same question here. I would love to build this wonderful pedal! regards

PS: OMG, my first post here! Hello! 

[bnashville]

Anyone who has built this - can you estimate what you spent on parts? I'm looking for a tap tremolo and would love to build it, but if the cost and time will exceed that of a commercially available pedal, I might go that route. To that same end, @drolo, do you still have PCBs available?

[chuckd666]

Vactrols are around $10 each (depending on the source I suppose), buying a pre programmed TAPLFO will probably set you back a similar amount, and all the other miscellaneous parts probably another $25-35 depending on enclosures etc. Add more for shipping! I dunno. I think in Australian dollars by the way. 

I'm not sure if it's easy to find any decent tap tempo tremolos, so if you're experienced with DIY, I'd give this a go. If you're a newbie though, I'd begin with simpler circuits. That said, if you can source one of Rolo's excellent PCBs it might be doable for you.

[dbp512]

I priced it out recently and it looks like it would cost about $50 plus shipping and an enclosure. The vactrols and taplfo chip are from smallbear, and the rest for tayda. If you wait for one of their monthly sales you could save a bit. I want to build this and a liquid mercury (I don't look forward to that on vero). I'm really hoping I can get pcb's for these.

[bnashville]

Thanks for the quick replies. It sounds like this would be a great project for a pretty reasonable price if I can track down a pcb or layout file. I know enough to follow a schematic pretty well, but not enough to make too many changes - does anyone know what it would take to make this stereo?